Source

Details

Note that in 2015 it was determined that the stations with codes ACO, AJU,
INN, MON and MPA would no longer be taken into consideration when computing
the pollution index because they didn't meet the
objectives
of monitoring air quality, and are no longer included in the index, even if
they are still part of the SIMAT (Sistema de Monitoreo Atmosférico de la
Ciudad de México). Thus, even if they are located inside a zone, they are not
included in the pollution values for that zone.

A transparency request was used to determine the zone to which the
municipios of Acolman, Texcoco and Atenco belong.